How did Apollo crew member Gwen McAllister die in 1971?

I was looking through this memorial list and noticed the year 1971 listed for two people who were on the Apollo. It occurred to me the Apollo was still at sea that year so it was possible they died on board.

I confirmed that the first person, Stella King, had indeed died on board of a heart attack, probably after being replaced as captain for running the ship aground twice.

Then there's Gwen McAllister who I'm getting no results on from searching. The only information I have on her is from that Waybacked page I first linked to: died in 1971, and was aboard the Apollo.

Someone remembered her in 2006. Will someone remember more about her, including how she died, in 2016?

Feel free to crosspost this wherever.

maybe Hanna Whitfield can shed some light?

I searched for anything on her for about two hours earlier today. I even went into some of the ancestry sites I work on. Zilch.

RO has a good idea...someone needs to contact Hana Whitfield and see if she knows anything.